As Readdle announced on their blog on November 20th, they updated their "solution for all your PDF needs" with PDF Expert 5. Readdle describes the update as following:

"PDF Expert 5 is a major upgrade for every person who reads, annotates or edits PDF documents on the iPad."

The five points of focus in this update are the new, clean, flat and iOS 7 style redesign, a completely revamped file manager with a bunch of new features, a new PDF Viewer with a full screen mode, a Text To Speech mode which makes use of iOS 7's text to speech API, and a brand new and revolutionary Review Mode.

When opening PDF Expert 5 for the first time, the app recognizes a previous version of PDF Expert and asks if you want to migrate from the old app. It then directs you to PDF Expert 4 where it opens the Migration Assistant, and after some time (depending on the amount of files it has to migrate) it takes you back to version 5 where it opens a "What's New" PDF. What's really nice is that it even imports your saved networks you were using in version 4.

The first thing you'll see when using the app is the completely new, flat and clean design which matches iOS 7's style. Compared to the previous version it's a huge improvement and even though it got the iOS 7 makeover, it still keeps PDF Expert's personality. The UI has been flattened, the colors adjusted, the folders look a lot more at home (on an Apple device), and the sidebar got a nice refresh with clean new icons.

Another great improvement over version 4 is the ability to show file name extensions (which I’d recommend as you can see whether you’re looking at a PDF, text, image, or other file) and that you can enable a feature called “Show Photos” which - after asking for your permission - will add a “Photos” folder to your Documents[1] showing your iPad’s Photo Library.

File Manager

The File Manager is where you manage all your files in PDF Expert 5. In the sidebar you have your Documents folder, the iCloud folder that also syncs with Readdle's Documents app, and Networks – after connecting to a network, it'll create a shortcut for it under a section called Accounts. Furthermore you'll find Favorites and Recents which will get added as soon as they are created.

To interact with your files you can either open them, tap Edit to change the sidebar into a menu, or Drag & Drop files to move them to other folders including the iCloud folder or your Dropbox, combine them with another file to create a folder (like you would on your Home Screen), add them as favorites, or delete them. The "Edit-Menu" offers some great things like copying or renaming a file (which can be really useful when using in Dropbox), merging several PDFs together, creating a Zip file, uploading files to your Dropbox, and more.

The reason I find those features interesting is because it lets me interact with Dropbox in different ways (especially when using it in pair with Documents and PDF Converter). I would even say that you could use PDF Expert (yes, an app for working with PDFs) as full blown Dropbox file manager.
When navigating through your Dropbox you can just tap on a file to copy it to your Documents Download folder[2]. When tapping the Edit button you can upload a file from your Documents or iCloud to the Dropbox folder you want and then share this file via Email or anywhere else (via Share link). If you happen to work on collaboration with others or create multiple versions of a document yourself, you can even view a revision list of your files.
One of the best things related to this deep Dropbox integration is the possibility to “Sync” a folder. You can enable a two-way synchronization between a folder in your Dropbox and a folder in your Documents. Those two folders will automatically be synced with each other which can save you a lot of time (and pain when forgetting to update a file you’re working on).
And to close this mini-review about the Dropbox integration, all this happens in the background which makes it even more enjoyable.

PDF Viewer

The PDF Viewer is where you'll actually be spending most of your time – and I think you'll enjoy the experience. The new polished design looks very clean and when tapping on the screen (in the middle, because tapping the left or right side lets you skip pages like in iBooks) you get a full screen mode that completely removes the UI. When swiping in from the left or right edge of the screen, it opens the annotation toolbar that can also be moved to the top, or simply swiped off from the screen again.

Besides having the usual annotation features, PDF Expert lets you add text, forms, add notes, create stamps, and add signatures. For even more precise annotations there's a features called "Smart Zoom" that lets you choose your tool, pinch to zoom and add your close-up annotation. And when talking about zooming in really close, it means a very detailed close-up zoom.

Another thing you might enjoy when working on PDFs for a long time is the "Reading Mode". You can adjust the iPad's brightness (which is only a swipe away anymore due to Control Center, but it can be practical when you're changing your reading experience), turn on Night or Sepia mode, change the scrolling behavior, or use Crop mode to remove margins.
When using Night mode it even removes the colors and turns them into different shades of grey instead of keeping the colors (in images for example) and just reversing the page background and text. Sepia puts a sepia-colored layer over the document doing the same thing with the colors as in Night mode but with a sepia colored tone. The only thing not changing in color is the UI, especially the annotation bar stays white no matter what mode you're using.

One thing that could also come in very handy is the new "Audiobook Mode" or Text To Speech functionality that uses iOS 7's text to speech API that reads out loud the text in the PDF. The app processes the text in the document and you can even jump to outlines or switch to the next paragraph.
In my tests it worked pretty fine in PDFs with simple text segments and paragraphs, but had some difficulties when a lot of pictures separated the paragraphs and the body text was between different headlines.

Review Mode

The biggest new feature in this update is Review Mode, and Readdle calls it their “one more thing” – also referring to it as a “new, revolutionary feature with no competition even among desktop PDF viewers” and “the biggest innovation in PDF annotation since highlights and text markups”.
What it does is that it allows you to markup and review PDF documents and shows you where you or someone else edited the text.[3] You can basically do the same things you would do on a collaborative text document, but on a PDF. Edit text, commit changes, even delete a whole paragraph. Don’t worry about what you change in the document as the text in the PDF itself will not be affected. The modifications are standard PDF annotations and can be edited in any decent PDF reader. The easiest way to work on the document though is to continue working on it in PDF Expert as it keeps the same format and doesn’t use several different font sizes (and fonts) or changes line heights etc.
In contrast to working on a text document with single lines, a PDF doesn’t have this linear structure and therefor can be a real pain when editing on several different platforms (and apps) – you also have to keep in mind that when working on a PDF and sending it around to edit it, one person should be the one having the master file to complete working on it in the end.

The short video below gives you a preview of Review Mode in action.

When saving a copy of the file you get three different formats:
- Original Document: It saves the file as it is and changes can be seen and edited.
- Flattened Copy: Your changes can be seen in the PDF, but can not be edited by another person using this document.
- Annotation Summary: It gives you a summary of your annotations and creates a text document.[4]

Additional features

Here are some additional features I appreciated when using the app:
- When long pressing the Undo button while annotating or in “Review Mode”, you can undo/redo actions several times.
- The app has a nice integration with other Readdle apps like PDF Converter[5], Documents[6] and Scanner Pro[7].
- Long tapping on a file in Recents or Favorites open a pop-up that lets you reveal the file, remove it from the list or clear all.
- When opening the Network section of the app “Available devices” are shown that are using the same network. After entering your authorization information you can access the device (like your Mac) and go through your folders to copy the files you need to your iPad.
- Another way of moving files from your Mac to PDF Expert is to use Wi-Fi Drive to connect to your iPad via browser of WebDAV app.
- In Settings you can enable Indexing for File Contents Search to enable the search feature inside documents.
- And last but not least, PDF Expert supports GIFs! Imagine the possibilities![8]

PDF Expert 5 comes as a new app and is available in the App Store for $9.99. It supports iOS 6 and iOS 7 and is compatible with the iPad 2 and later.
PDF Expert 4 will still be around and maintained for the next year and it’s up to you if you update, but as with other recent app updates you might want to jump on the new iOS 7 designed version of it.

In Settings you have the possibility to change the locations to where files get downloaded to either the “Downloads” directory, the same directory as on a server, or set it to ask for a directory. ↩

Before editing something for the first time the app asks for an Author name to identify who committed changes to the document. The name can be changed in Settings later as well. ↩

You can then open the text document in a text processing app via “Open in”, or convert it into a PDF using Readdle’s PDF Converter – it opens up PDF Converter (if installed), converts it, takes you back to PDF Expert and opens the newly created PDF. ↩

As mentioned in the previous footnote, you can convert files to PDFs using PDF Converter. This works for example with text files, images, Powerpoint, Excel, Pages, HTML documents, etc. but it doesn’t seem to convert Numbers documents. ↩

Readdle creates an iCloud folder called “ReaddleDocsIPad” which it uses to keep Readdle Documents and PDF Expert 5’s iCloud folder in sync. ↩

When opening a scanned file in Scanner Pro you have a dedicated button (underlined A) that opens the PDF in PDF Expert ↩

The only real thing you can do with it is opening it in another app or send it by Email – but sending it by Email is a pretty good thing, right? ↩